Abstract: In this study, we investigated the community structure of benthic macro-invertebrates in the inflowing rivers of Lake Gehu in April of both 2018 and 2019, and evaluated water quality using biological indices. Twenty-eight species of benthic macro-invertebrates were identified in the inflowing rivers of Lake Gehu. Limnodrilus hoffmeisteri (dominance index: 0.46) with high pollution resistance and Bellamya aeruginosa (dominance index: 0.11) with moderate pollution resistance were the dominant species. In terms of biodiversity, Hexi River was the highest, followed by Huangli and Biandan rivers; Xiaxi River and the estuary into the lake were the lowest. The distribution of aquatic plants might be one of the most important factors determining the diversity of benthic macroinvertebrates in different regions. The Carlson nutrition status index was consistent with the biological indices in water quality assessment. With the extension of Xinmeng River and dredging project, the middle and upper reaches of Hexi, Xiaxi, and Huangli rivers were at a moderate eutrophication level, with water body being lightly to moderately polluted; whereas the lower reaches of Biandan River and estuaries into the lake were at a severe eutrophication level, with water body being moderately to heavily polluted.

Key words: endophyte, parasitic plant, medicinal plant, interaction